The MU School of Medicine made a breakthrough in research for a treatment for muscular dystrophy that has been more than 10 years in the making.
Dr. Dongsheng Duan and a medical research team in the School of Medicine developed and published a Jan. 13 study on dystrophin gene therapy for the muscular disorder Duchenne Muscular Dystrophy. The breakthrough could lead to human testing of the treatment in the future, Duan said.
DMD is the most severe of the nine genetic disorders, according to the Muscular Dystrophy Association’s website. DMD causes muscles to slowly degenerate, leading to muscle weakness and, eventually, complete paralysis and death.
Though women generally carry the disorder, DMD symptoms generally occur in men, the MDA website states. The disorder rarely appears in women and carriers often show no symptoms.
Symptoms, which include difficulty sitting up and ascending stairs, usually begin to show between the ages of 3 and 5. Over time the DMD progresses to paralyze the legs, restricting the patient to a wheel chair, and then paralyzes the rest of the body. The MDA website states, “survival into the early 30s is becoming more common, and there are cases of men living into their 40s and 50s.”
“Patients with DMD have a gene mutation that disrupts the production of dystrophin, a protein essential for muscle cell survival and function,” an MU News Bureau press release said. “Absence of dystrophin starts a chain reaction that eventually leads to muscle cell degeneration and death.”
For the treatment that Duan’s team developed, a miniaturized form of the dystrophin gene is the key.
“Basically, we designed a highly miniaturized dystrophin gene and engineered the microgene into a harmless viral capsid,” Dr. Duan said in an email. “The vector was then injected into the muscle of a diseased dog and two months after treatment, we examined the results.”
The dogs treated did not reject the injected microdystrophin like other subjects in previous studies, the MDA’s magazine publication Quest said. In contrast to past studies, the results showed the injected microdystrophin encouraged regular dystrophin production in the muscles.
“This is the first demonstration that a microgene can work in a disease muscle of a large mammal,” Duan said. “This set the foundation to apply a similar approach to treat the disease in human patients.”
Duan said the development was a “quantum leap forward” in research for a possible cure.
“We are one step closer to apply gene therapy to treat the disease,” Duan said. “If it works, this will effectively alleviate muscle disease in all DMD patients irrespective the particular gene mutation the patient has.”
Though there is no timeline for beginning human testing of the gene therapy as of yet, the MDA remains hopeful that the treatment will soon come to fruition.
“MDA has been supporting DMD gene therapy for nearly 30 years, and this success is a significant step forward,” MDA Vice President of Research Jane Larkindale said. “Dr. Duan has clearly demonstrated that his microgene can have a significant effect on the symptoms of a large animal model of Duchenne Muscular Dystrophy. With MDA’s ongoing support for further studies, we hope that Dr. Duan and other researchers are successful in making this therapy a reality.”
The full results of Duan and the School of Medicine research team’s study can be found in the scientific journal Molecular Therapy.